1. Field of the Invention
The present invention relates to a semiconductor manufacturing apparatus, a method for cleaning the semiconductor manufacturing apparatus, and a light source unit, and more particularly, to a semiconductor manufacturing apparatus for coating the surface of a semiconductor wafer with an organic film such as anti-reflective coating, a method suitable for cleaning the semiconductor manufacturing apparatus, and a light source unit suitable for performing the cleaning method.
2. Description of the Background Art
Processes for manufacturing a semiconductor device include a process for forming an organic film, such as a resist film or anti-reflective coating (ARC), on a semiconductor wafer. Such an organic film is usually formed by spin-coating a semiconductor wafer with organic material and baking the semiconductor wafer on a hot plate.
The organic material often contains compounds that tend to sublime (hereinafter called xe2x80x9csublimation compoundsxe2x80x9d). The sublimation compounds contained in the organic material sublime to gaseous form while the semiconductor wafer is baked on the hot plate, rise to a top plate of the hot plate unit, and adhere to the top plate. If an organic film is formed while a large amount of organic compounds adhere to the top plate, the semiconductor wafer may be contaminated by the compounds. In order to work around the contamination, the top plate of the hot plate unit is removed every time a predetermined number of semiconductor wafers have been processed, and the sublimation compounds are manually removed through use of an organic solvent.
In order to manually remove the compounds adhering to the top plate, the hot plate, which is heated to a temperature of about 100 to 200xc2x0 C. under normal operation, must be cooled to close to room temperature before removal of the top plate. Thus, the conventional cleaning method encounters a problem of lengthening a period of time during which the semiconductor manufacturing apparatus provided with the hot plate unit becomes idle in association with cleaning of the top plate. Hereinafter, the period of time is referred to as xe2x80x9cdown time.xe2x80x9d Further, the above-described conventional method under which the compounds adhering to the top plate are manually removed through use of the organic solvent involves a safety problem.
The present invention has been conceived to solve such problems involved in the conventional cleaning method, and a first object of the present invention is to provide a semiconductor manufacturing apparatus which enables a reduction in down time associated with removal of sublimation compounds, as well as safe and simple removal of the compounds.
A second object of the present invention is to provide a method for cleaning a semiconductor manufacturing apparatus which is suitable for safely and simply removing sublimation compounds adhering to the semiconductor manufacturing apparatus provided with a hot plate, within a short period of time.
A third object of the present invention is to provide a light source unit useful for performing the cleaning method.
The above objects of the present invention are achieved by a semiconductor manufacturing apparatus including a heating unit for heating a semiconductor wafer. The apparatus includes a top plate which is positioned above a semiconductor wafer to be processed within the heating unit. The top plate has a facing surface facing to the semiconductor wafer and a non-facing surface provided opposite side of the facing surface. The apparatus also includes a light source unit for radiating light including UV-rays having a predetermined wavelength onto the facing surface of the top plate.
The above objects of the present invention are also achieved by a method for cleaning a semiconductor manufacturing apparatus including a heating unit for forming an organic film on the surface of a semiconductor wafer. In the method, a top plate of the heating unit is exposed to light including UV-rays having a predetermined wavelength while the semiconductor wafer is transported out of the heating unit.
The above objects of the present invention are further achieved by a light source unit for radiating light including UV-rays having a predetermined wavelength onto a top plate of a heating unit for forming an organic film on the surface of a semiconductor wafer. The unit includes a circular housing whose diameter is substantially equal to that of the semiconductor wafer. A plurality of lamps are arranged over the entire interior area of the housing at substantially uniform density. The lamps illuminate light including UV-rays having the predetermined wavelength. A power supply unit is also housed within the housing for supplying power to the lamps. The light source unit is designed so as to be less than 4 cm in the height thereof.
Other objects and further features of the present invention will be apparent from the following detailed description when read in conjunction with the accompanying drawings.